1. Field of the Invention
The present invention relates to vehicle toys and their suspension systems, particularly the suspension of steerable road wheels.
2. Description of the Prior Art
In general, since vehicle toys are subjected to the influence of a rough road surface in travelling, some of the vehicle toys are provided with a suspension system for connecting a body of the vehicle toy with wheel axles thereof through springs, links and shock absorbers so as to absorb road shocks. In this way, the vehicle toy itself is protected from road shocks which are also damped to improve the vehicle toy in roadability. Heretofore, the suspension system employed in the vehicle toy has been, for example, a swing-arm type, a double-wishbone type, a rigid-axle type, or the like.
As shown in FIG. 11 of the accompanying drawings, a suspension system 100 of a swing-arm type is an independent mechanism provided in each of opposite sides of the vehicle toy. In this system 100, a swing arm 104 has one end pivotally connected with a chassis 102, and rotatably supports at its other end an upright member 108. A steerable wheel 106 is mounted on the upright member 108 through a wheel axle 105. A spring 109 is interposed between an upper portion of the chassis 102 and the other end of the swing arm 104. Although the suspension system 100 of this swing-arm type is simple in construction, the system 100 is disadvantageous in that an inclination of the wheel 106 to the vertical becomes large when the swing arm 104 moves up and down.
As shown in FIG. 12 of the accompanying drawings, a suspension system 110 of the double-wishbone type is an independent mechanism provided on each of opposite sides of the vehicle toy. In the system 110, each of a pair of swing arms 112, 112 has one end pivotally connected with the chassis 102, and pivotally supports at its other end an upright holder 114. Supported by this upright holder 114 is an upright rotatable member 116 to which a wheel 106 is rotatably mounted. A compression spring 118 is interposed between an upper portion of the chassis 102 and the upright holder 114. In this double-wishbone type suspension system, there is no inclination of the wheel 106 when the pair of the swing arms 112 move up and down. However, in construction, this system is complex, which leads to a high cost thereof which is a disadvantage of this system.
As shown in FIG. 13 of the accompanying drawings, in a suspension system 120 of the rigid-axle type, a connecting axle 122 connects left and right wheels 106, 106, and rotatably supports at its opposite end portions a pair of upright members 124, 124. Mounted on these upright members 124, 124, through a pair of axles 105, 105, are the left and right wheels 106, 106. A pair of compression springs 126, 126 are interposed between an upper portion of the chassis 102 and the opposite end portions of the wheel axle 122. In this rigid-axle type suspension system, there is no inclination of the left and the right wheel 106, 106 when the wheel axle 122 moves up and down. However, since the left and right wheels 106, 106 move up and down as a whole at the same time, the suspension system does not function properly and is disadvantageous when the vehicle toy is subjected to an inclining force produced during cornering of the vehicle toy, which inclining force causes the vehicle toy when of a high-speed type and an off-road type to tend to overturn.